Falling in the elderly is a complex problem caused by the dynamic interaction of multiple intrinsic and extrinsic factors. It is difficult to determine a reason why a particular elder falls, and then to evaluate strategies to reduce future falls. Standard physical examination techniques are limited in detecting mobility impairment. Most other methods of testing balance, gait, and mobility are impractical for general clinical use. Most methods also neglect to evaluate the functional interaction an elder experiences in his or her personal environment, where most falls occur (person-environment interface). An elder's daily activities pose subtle, but important deficits seldom detected by the clinician. Our proposed strategy is to evaluate the balance and mobility of elderly subjects, while performing a series of functional tasks under various conditions that mimic everyday life. We will do this by constructing an obstacle course with everyday obstacles, such as stairs, ramps, uneven or loose footing surfaces, etc. Ranges of performance will be determined for elders who fall and those who do not. We will then determine if performance scores predict future falls and injuries. In a separate group of elders, obstacle course performance will be used to assess short and long- term response to rehabilitation intervention. The efficacy and predictive value of a low-cost, low technology, functionally oriented obstacle course, designed to evaluate elderly persons who fall and to evaluate their response to intervention, will be determined. The preliminary data indicate that this approach will provide reliable, reproducible evaluation. Specific Aims of this study are to: 1. Construct an obstacle course, establish normal ranges of performance scores and validate the scores as measures of balance and mobility in a population of elderly subjects. 2. Determine the efficacy of obstacle course performance scores in predicting those at risk for falls, after adjusting for differences in health-status, age and other socio-demographic variables. 3. Determine the efficacy of a structure, balance rehabilitation training program (BRP) to improve the balance and mobility of elderly subjects and to further validate the obstacle course (relative to the 2 other indices) as a measure of change in such an intervention setting. This study will provide clinicians with the scientific basis for using the proposed obstacle course to better investigate and reduce falling and fall-related injuries.